launder vs launderess

launder

noun
  • A trough or channel carrying water to the wheel of a watermill. 

  • A gutter (for rainwater). 

  • A trough used by miners to receive powdered ore from the box where it is beaten, or for carrying water to the stamps, or other apparatus for comminuting (sorting) the ore. 

verb
  • To disguise the source of (ill-gotten wealth) by various means. 

  • To wash; to wash, and to smooth with a flatiron or mangle; to wash and iron. 

launderess

noun
  • A female launderer. 

How often have the words launder and launderess occurred in a corpus of books? (source: Google Ngram Viewer )